How to Grow Potatoes
Potatoes are a staple food in many households, and you might be surprised to learn how easy they are to grow! Each plant doesn't need much space to grow, and they'll be just as successful in the right containers and grow bags as they are in the field. If you want to add potatoes to your gardening repertoire, here are our best tips and tricks for a successful harvest.
Seed potatoes are actually small potato tubers that will grow and produce more potatoes when planted. Seed potatoes have "eyes," which begin as small dimples on the surface of the potatoes and turn into sprouts that will, in turn, become plants. Each seed potato may have multiple eyes, and seed potatoes will often be cut into multiple pieces before planting to maximize production. If you cut your seed potatoes, use a sharp, clean knife and allow them to callous over before planting to prevent disease. Each piece should have 1-2 eyes; small seed potatoes can be planted whole. We recommend purchasing new seed potatoes each year to be certain your crop is disease and pest-free for a high-quality yield.
Soil and Compost
Potatoes love organic matter and light, loose, moisture-retentive soil. Your soil should be slightly acidic (5.0 to 6.0), which will help reduce the risk of a disease called potato scab. We recommend amending your beds and containers with composted organic matter like cow and sheep manure or sea compost. To prevent the spread of disease and the overuse of nutrients, potatoes should not be grown in the same spot two seasons in a row. Ideally they should be put on a 3-year cycle, moving them to a different location each season.
Potatoes can be easily grown in a variety of containers. Be sure to choose a container with drainage, and look for one that is about 2' (60cm) high with a 10 gallon (30l) capacity. Grow bags, potato tubs, and burlap sacks are great options for potatoes as they can be rolled up as the season progresses. We're also a big fan of these Potato Patch containers, as they're great for small spaces and make harvest extremely easy! Don't crowd your seed potatoes in containers, or they won't have room to grow.
Seed potatoes can be planted as soon as the ground is workable in the early spring (generally April-May). The soil temperature should be 7 degrees C or warmer. Potatoes will tolerate light frost, but frost protection is recommended when planting early in the season to prevent damage.
Loosen the soil in your bed with a rake and remove any large rocks or debris. Work in a generous amount of compost, which will both provide nutrients and help ensure your soil is light and drains well. Some gardeners grow potatoes directly in compost, but this should be done carefully as a mix too high in nitrogen will produce plants with excessive foliage and poor yields. Compost that has not been properly broken down can harbour pests and diseases. Avoid planting potatoes in low areas with poor drainage, as overly wet soil can cause potatoes to rot.
For potatoes in containers, choose a potting soil that's light and airy rather than a heavy garden soil or topsoil and amend with compost and/or slow release fertilizer. Fill containers with 4"-6" of soil to start.
To plant potatoes in rows in a garden bed, dig a trench 4” wide and 6”-8” deep and make sure your soil is well hydrated without being over-saturated when you plant. Leave 28”-36” of space between each row. Place each seed potato 15” apart, cut side down (whole, small seed potatoes can be placed with eyes facing up). Fill the trench with 3”-4” of soil.
To plant potatoes in containers, place your seed potatoes at least 5" apart and cover with a few inches of soil (no more than 4"). Generally, you can fit 2-4 potatoes in a 10 gallon pot, and about 6 in a 20 gallon pot. The more crowded your container is, the smaller and fewer potatoes your plants will produce.
Weather pending, sprouts should appear about two weeks after planting.
Once the plant has grown to 8” high, hill up soil around each stem about 4" high while being careful not to disturb the roots below the soil. Repeat this process in another two weeks. This keeps developing potatoes cool and protected from sunlight and pests. Some gardeners will add straw on top of the soil around potatoes, which makes an ideal mulch as it still allows airflow to the soil.
Throughout the growing season, keep your soil evenly moist. The most crucial time for watering is during and after the period when the plant is in flower, as this is the time that the plant is creating new tubers. If you're growing potatoes in containers, be extra vigilant with your watering and ensure the soil is not allowed to dry out between waterings.
Monitor plants regularly for signs of insects and disease. Spacing plants to allow for adequate airflow can help prevent the spread of blights and other fungal infections. At the first sign of disease, remove any infected leaves and spray with an appropriate fungicide.
Once the foliage of the plant turns yellow and dies back, stop watering. At this point, you can check below the soil for new potatoes to harvest and eat immediately.
Once tubers have reached their desired size, you can cut or mow back the vines above the soil. Allow the tubers to sit in the ground for two to three weeks before harvest; some gardeners will leave potatoes to harvest after the first frost. Turn the soil carefully when harvesting, and be cautious of stabbing the tubers. Allow your potatoes to dry and cure for around a week in a cool, dry area. This allows their skin to thicken for better storage life. You can brush or gently rinse the soil from your potatoes before leaving them to cure, but avoid scrubbing and ensure your potatoes are fully dry before placing them in storage. Store your potatoes in a dark, cool area with moderate humidity to prevent sprouting and shrivelling. Depending on variety, temperature, and humidity, potatoes can keep for many months in storage.